The ultimate objective of this small grant study is to increase the effectiveness of family-based therapy for adolescent drug abuse, which is building solid empirical support as an efficacious treatment approach. This study will seek to identify family-related treatment processes associated with reducing drug use in a primarily urban, African American, juvenile justice-involved sample. The attempt to illuminate links between specific therapeutic interventions and positive treatment outcomes is vital to developing more effective, targeted, and transportable therapy models for dissemination in the treatment community. First, the proposed study will examine the importance of therapist efforts to centralize family members and family or individual-based therapy. Adolescents and parents completed measures of adolescent drug use and family functioning (cohesion, parental investment), and videotaped therapy sessions and therapist contact logs will be reviewed to assess the degree of family involvement in each treatment condition. Structural equation modeling will be used to test the following mediational hypotheses: family therapy will lead to comparatively greater reduction in drug use by means of involving family members to a greater extent in treatment, and moreover, it will produce these gains by means of improving family functioning over the course of therapy. Second, the proposed study will explore the success of family therapy in enhancing a crucial ingredient of healthy adolescent development: autonomous-relatedness family interactions. A subsample of 18 family therapy and 11 individual therapy cases participated family interaction tasks that will be coded for family behaviors that support individuation while also providing a secure relationship base for the adolescent. Exploratory correlational analyses will be used to test the hypotheses that family therapy will produce greater gains in autonomous-relatedness and that these gains will be associated with improvement in adolescent drug use and other aspects of family functioning. This study will be among the first to use observational methods for linking family-focused interventions with outcome and for exploring changes in developmentally pivotal family processes in treatment for substance-abusing adolescents.